The invention concerns a rotary potentiometer device having a rotary potentiometer disposed within a housing and a handle above the housing by means of which a resistive disk of the rotary potentiometer can be rotated and with a latching device for latching the handle with the upper side of the housing in predetermined rotated positions.
Rotary potentiometer devices are capable of tapping a desired resistance between a minimum value and a maximum value with the assistance of a sliding contact on a sliding contact resistive track by rotating an adjustment wheel attached to the sliding contact, wherein the minimum value and the maximum value are defined by two end stops of the sliding contact. The sliding contact resistive track can be rotated instead of the sliding contact. Conventional rotary potentiometer devices have a latching device for latching the adjustment wheel with the upper side of the housing in predetermined rotated positions to change the resistance through rotation of the adjustment wheel in a non-continuous discrete manner.
In a conventional rotary potentiometer device having such a latching device, a ball is guided in an axially displaceable fashion within a bottom hole in the upper side of the housing opening towards the lower side of the adjustment wheel and protrudes beyond the upper side of the housing towards the adjustment wheel. In this protruding position, the ball is loaded by a helical spring supported on the bottom of the bottom hole. The protruding ball cooperates with latching protrusions on the lower side of the adjustment wheel such that a particular torque is necessary when rotating the adjustment wheel to swing the adjustment wheel or the latching protrusions against the resistance of the protruding ball. In this manner, the adjustment wheel has fixed angular positions and thereby the potentiometer has defined resistor values or defined changes in the resistor values.
The conventional rotary potentiometer requires a plurality of individual components to form the latching device having the ball and helical spring which necessitate additional processing steps and which could be lost.
It is therefore the purpose of the present invention to improve a rotary potentiometer device of the above-mentioned kind in such a fashion that the latching device is particularly simple and can be made without great difficulty or expense.